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SUMMARY:**WITHDRAWN** Particle vs. Mode Entanglement in Quantum Enhanced O
ptical Metrology
DTSTART;VALUE=DATE-TIME:20150618T011600Z
DTEND;VALUE=DATE-TIME:20150618T011800Z
DTSTAMP;VALUE=DATE-TIME:20210128T130055Z
UID:indico-contribution-841678@indico.cern.ch
DESCRIPTION:Speakers: Nicolas Quesada (University of Toronto)\nWe describe
the role of mode and particle entanglement in Quantum Enhanced Optical M
etrology (QEOP).\nTo this end we study the properties of the quantum Fishe
r information $\\mathfrak{F}$ that bounds from \nbelow the sensitivity $\\
Delta^2 \\varphi$ of any phase estimation protocol $\\Delta^2 \\varphi \\g
eq 1/\\mathfrak{F}$.\nWe recently showed [1] that the optimal measurement
sensitivity of quantum light in a path symmetric Mach-zender interferomete
r depends on its inter-mode correlations and intra-mode correlations in t
he following manner $ \\mathfrak{F}=\\bar{n} (1+\\mathcal{Q})(1-\\mathcal{
J})$ \nwhere $\\bar{n}$ is the total number of photons in the MZI (assumed
to be equally distributed in both arms)\,\n$\\mathcal{Q}$ is the Mandel $
\\mathcal{Q}$ parameter (assumed to be the same for the two modes) and $\\
mathcal{J}$ is the mode correlation parameter.\n\nThe intra-mode correlati
ons in the form of non-classical counting statistics associated with the $
\\mathcal{Q}$ parameter of each arm of the interferometer are identified w
ith particle entanglement whereas the inter-mode correlations in term of $
\\mathcal{J}$ are associated with mode entanglement. \n\nWe discuss the ef
fects of each type of entanglement in phase estimation and show that mode
entanglement is not necessary for quantum enhanced sensitivity and that pa
rticle entanglement is always necessary for an enhancement\, but\, it is a
lso always necessary for a suppression of sensitivity.\n\nIn more general
terms we show that particle entanglement does not fit the usual notions\no
f a resource for QEOP since one can map states that are useful for QEOP to
states that are not via particle local operations.\n\n[1] J. Sahota and N
. Quesada\, Phys. Rev. A **91**\, 013808 (2015)\n\nhttps://indico.cern.ch/
event/355942/contributions/841678/
LOCATION:University of Alberta CCIS Ground Floor PCL lounge
URL:https://indico.cern.ch/event/355942/contributions/841678/
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